Tag Archives: Camponotus modoc

Camponotus modoc Wheeler: Modoc Carpenter Ant

California Pest Rating for
Camponotus modoc Wheeler: Modoc Carpenter Ant
Hymenoptera: Formicidae
Pest Rating:  C

Initiating Event:

At least one ant hobbyist is selling queen ants of Camponotus modoc in California.1  A pest rating proposal is required to determine future direction on this ant.

History & Status:

Background:  Camponotus modoc is a carpenter ant that inhabits montane forests.2,3  It is a generalist forager on dead and living insects, nectar, fruit juices, and honeydew2.  It nests by excavating galleries in wood such as trees, wood piles, and landscaping materials2.  Colonies may be transported long distances when infested wood is moved.

Worldwide Distribution: Camponotus modoc is native to the western United States and Canada3.  It is not known to have invaded any other states or nations.

Official Control: Camponotus modoc is not known to be under official control in any other states or nations.

California Distribution Camponotus modoc is native to California and commonly found in montane forests.

California Interceptions:  Camponotus modoc was intercepted once by CDFA’s border stations in pine firewood from Nevada.

The risk Camponotus modoc (Modoc Carpenter Ant) would pose to California is evaluated below.

Consequences of Introduction: 

1) Climate/Host Interaction: Camponotus modoc is native to and widespread in California and is not likely to establish in parts of the state where it does not already occur. It receives a Low (1) in this category.

Evaluate if the pest would have suitable hosts and climate to establish in California.  Score:

Low (1) Not likely to establish in California; or likely to establish in very limited areas.

Medium (2) may be able to establish in a larger but limited part of California.

High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Camponotus modoc is a generalist forager and is considered a destructive pest when it excavates galleries in wooden structures.  It receives a Medium (2) in this category.

Evaluate the host range of the pest. Score:

Low (1) has a very limited host range.

Medium (2) has a moderate host range.

High (3) has a wide host range.

3) Pest Dispersal Potential: Ants typically have high reproductive rates.  Camponotus modoc has only been intercepted by CDFA once.  It receives a Medium (2) in this category.

Evaluate the natural and artificial dispersal potential of the pest. Score:

Low (1) does not have high reproductive or dispersal potential.

Medium (2) has either high reproductive or dispersal potential.

High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Camponotus modoc is already widespread and is not known to have lowered any crop yields or reduced crop values.  Its presence has not disrupted any markets.  It has not changed cultural practices or vectored other organisms.  It is not known to have injured any animals or interfered with any water supplies.  It receives a Low (1) in this category.

Evaluate the economic impact of the pest to California using the criteria below. Score:

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Low (1) causes 0 or 1 of these impacts.

Medium (2) causes 2 of these impacts.

High (3) causes 3 or more of these impacts.

5) Environmental Impact: Camponotus modoc is native to and widespread in California and it has not been found to lower biodiversity, disrupt natural communities, or change ecosystem processes.  It has not affected any threatened or endangered species or disrupted critical habitats.  The ant does trigger additional treatment programs when it infests wooden structures2Camponotus modoc is not known to have impacted cultural practices, home/urban gardening, or ornamental plantings.  It receives a Medium (2) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

Score the pest for Environmental Impact. Score:

Low (1) causes none of the above to occur.

Medium (2) causes one of the above to occur.

High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Camponotus modoc (Modoc Carpenter Ant):  Low (8)

Add up the total score and include it here.

Low = 5-8 points

Medium = 9-12 points

High = 13-15 points

6) Post Entry Distribution and Survey Information: Camponotus modoc is considered to be widespread and common in California. It receives a High (-3) in this category.

Evaluate the known distribution in California. Only official records identified by a taxonomic expert and supported by voucher specimens deposited in natural history collections should be considered. Pest incursions that have been eradicated, are under eradication, or have been delimited with no further detections should not be included.

Not established (0) Pest never detected in California, or known only from incursions.

Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

The final score is the consequences of introduction score minus the post entry distribution and survey information score: Low (5)


There is low uncertainty with this ant.

Conclusion and Rating Justification:

Camponotus modoc is a native ant that is widespread in California and is not reported to have had any negative economic impacts.  It may have limited environmental impacts by triggering new chemical treatments when it infests wooden structures.  No significant impacts are expected from hobbyists trading colonies of this ant within the state, provided that they adequately protect against the escape of colonies or queen ants into urban and rural residential environments.


1 The AntsCanada Global Ant Nursery Project.  http://www.antscanada.com/queen-ants-for-sale/

2 UC IPM: How to Manage Pests of Homes, Structures, People, and Pets: Carpenter Ants:  http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7416.html

3 AntWiki: Camponotus modoc  http://www.antwiki.org/wiki/Camponotus_modoc

Responsible Party:

Jason Leathers, 1220 N Street, Sacramento, CA, 95814, (916) 654-1211, plant.health[@]cdfa.ca.gov.

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Pest Rating:  C

Posted by ls